This invention relates to a processing tool for processing a material to be processed (hereinafter referred to as "processed material") represented by a hard and brittle material (hereinafter referred to as "brittle material") such as glass or ceramic, a metal material, or the like, and more particularly to an ultrasonic vibration composite processing tool for carrying out processing of a processed material by grinding, polishing, cutting or the like while applying vibration to the processed material during processing of the processed material.
In order to ensure satisfactory processing of a processed material such as a brittle material, a metal material or the like into a predetermined or desired size by infeed and permit a surface of the processed material which has been subject to processing to exhibit properties of a desired level, it is required to reduce processing force which is applied to the processed material during the processing, to thereby permit a processing member to exhibit a satisfactory processing performance, resulting in eliminating dressing as much as possible when the processing member is, for example, a grinding wheel.
In general, when a vibrator is used to apply vibration to a processing member, an increase in diameter of the processing member to a degree as large as, for example, 100 mm or more renders smooth processing substantially impossible. This causes advantages such as a reduction in processing force and the like obtained due to the vibrator to be lost.
A substrate such as a glass substrate for a liquid crystal display device, a glass substrate for a plasma display device, a glass substrate for a thermal head, a ceramic substrate for a hybrid IC or the like tends to be increased in size with the years. Unfortunately, a processing tool for uniformly processing a surface of the substrate at an increased speed has not been developed in the art.